<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html lang="en" dir="ltr" class="client-nojs">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Variadic functions - cppreference.com</title>
<meta charset="UTF-8">
<meta name="generator" content="MediaWiki 1.21.2">


<link rel="shortcut icon" href="../../favicon.ico">



<link rel="stylesheet" href="../../common/ext.css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" href="../../common/site_modules.css">
<style>a:lang(ar),a:lang(ckb),a:lang(fa),a:lang(kk-arab),a:lang(mzn),a:lang(ps),a:lang(ur){text-decoration:none}#toc{display:none}.editsection{display:none}
/* cache key: mwiki1-mwiki_en_:resourceloader:filter:minify-css:7:472787eddcf4605d11de8c7ef047234f */</style>

<script src="../../common/startup_scripts.js"></script>
<script>if(window.mw){
mw.config.set({"wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"c/variadic","wgTitle":"c/variadic","wgCurRevisionId":71747,"wgArticleId":13690,"wgIsArticle":true,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":[],"wgBreakFrames":false,"wgPageContentLanguage":"en","wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy","wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgMonthNamesShort":["","Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"],"wgRelevantPageName":"c/variadic","wgRestrictionEdit":[],"wgRestrictionMove":[]});
}</script><script>if(window.mw){
mw.loader.implement("user.options",function(){mw.user.options.set({"ccmeonemails":0,"cols":80,"date":"default","diffonly":0,"disablemail":0,"disablesuggest":0,"editfont":"default","editondblclick":0,"editsection":0,"editsectiononrightclick":0,"enotifminoredits":0,"enotifrevealaddr":0,"enotifusertalkpages":1,"enotifwatchlistpages":0,"extendwatchlist":0,"externaldiff":0,"externaleditor":0,"fancysig":0,"forceeditsummary":0,"gender":"unknown","hideminor":0,"hidepatrolled":0,"imagesize":2,"justify":0,"math":1,"minordefault":0,"newpageshidepatrolled":0,"nocache":0,"noconvertlink":0,"norollbackdiff":0,"numberheadings":0,"previewonfirst":0,"previewontop":1,"quickbar":5,"rcdays":7,"rclimit":50,"rememberpassword":0,"rows":25,"searchlimit":20,"showhiddencats":0,"showjumplinks":1,"shownumberswatching":1,"showtoc":0,"showtoolbar":1,"skin":"cppreference2","stubthreshold":0,"thumbsize":2,"underline":2,"uselivepreview":0,"usenewrc":0,"watchcreations":0,"watchdefault":0,"watchdeletion":0,
"watchlistdays":3,"watchlisthideanons":0,"watchlisthidebots":0,"watchlisthideliu":0,"watchlisthideminor":0,"watchlisthideown":0,"watchlisthidepatrolled":0,"watchmoves":0,"wllimit":250,"variant":"en","language":"en","searchNs0":true,"searchNs1":false,"searchNs2":false,"searchNs3":false,"searchNs4":false,"searchNs5":false,"searchNs6":false,"searchNs7":false,"searchNs8":false,"searchNs9":false,"searchNs10":false,"searchNs11":false,"searchNs12":false,"searchNs13":false,"searchNs14":false,"searchNs15":false,"gadget-ColiruCompiler":1});;},{},{});mw.loader.implement("user.tokens",function(){mw.user.tokens.set({"editToken":"+\\","patrolToken":false,"watchToken":false});;},{},{});
/* cache key: mwiki1-mwiki_en_:resourceloader:filter:minify-js:7:ca03345b1e2c4d90a25d968753a73b92 */
}</script>
<script>if(window.mw){
mw.loader.load(["mediawiki.page.startup","mediawiki.legacy.wikibits","mediawiki.legacy.ajax"]);
}</script>
<style type="text/css">/*<![CDATA[*/
.source-c {line-height: normal;}
.source-c li, .source-c pre {
	line-height: normal; border: 0px none white;
}
/**
 * GeSHi Dynamically Generated Stylesheet
 * --------------------------------------
 * Dynamically generated stylesheet for c
 * CSS class: source-c, CSS id: 
 * GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann
 * (http://qbnz.com/highlighter/ and http://geshi.org/)
 * --------------------------------------
 */
.c.source-c .de1, .c.source-c .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}
.c.source-c  {font-family:monospace;}
.c.source-c .imp {font-weight: bold; color: red;}
.c.source-c li, .c.source-c .li1 {font-weight: normal; vertical-align:top;}
.c.source-c .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}
.c.source-c .li2 {font-weight: bold; vertical-align:top;}
.c.source-c .kw1 {color: #0000dd;}
.c.source-c .kw2 {color: #0000ff;}
.c.source-c .kw3 {color: #0000dd;}
.c.source-c .kw4 {color: #0000ff;}
.c.source-c .co1 {color: #909090;}
.c.source-c .co2 {color: #339900;}
.c.source-c .coMULTI {color: #ff0000; font-style: italic;}
.c.source-c .es0 {color: #008000; font-weight: bold;}
.c.source-c .es1 {color: #008000; font-weight: bold;}
.c.source-c .es2 {color: #008000; font-weight: bold;}
.c.source-c .es3 {color: #008000; font-weight: bold;}
.c.source-c .es4 {color: #008000; font-weight: bold;}
.c.source-c .es5 {color: #008000; font-weight: bold;}
.c.source-c .br0 {color: #008000;}
.c.source-c .sy0 {color: #008000;}
.c.source-c .sy1 {color: #000080;}
.c.source-c .sy2 {color: #000040;}
.c.source-c .sy3 {color: #000040;}
.c.source-c .sy4 {color: #008080;}
.c.source-c .st0 {color: #008000;}
.c.source-c .nu0 {color: #000080;}
.c.source-c .nu6 {color:#000080;}
.c.source-c .nu8 {color:#000080;}
.c.source-c .nu12 {color:#000080;}
.c.source-c .nu16 {color:#000080;}
.c.source-c .nu17 {color:#000080;}
.c.source-c .nu18 {color:#000080;}
.c.source-c .nu19 {color:#000080;}
.c.source-c .ln-xtra, .c.source-c li.ln-xtra, .c.source-c div.ln-xtra {background-color: #ffc;}
.c.source-c span.xtra { display:block; }

/*]]>*/
</style>
<style type="text/css">/*<![CDATA[*/
.source-text {line-height: normal;}
.source-text li, .source-text pre {
	line-height: normal; border: 0px none white;
}
/**
 * GeSHi Dynamically Generated Stylesheet
 * --------------------------------------
 * Dynamically generated stylesheet for text
 * CSS class: source-text, CSS id: 
 * GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann
 * (http://qbnz.com/highlighter/ and http://geshi.org/)
 * --------------------------------------
 */
.text.source-text .de1, .text.source-text .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}
.text.source-text  {font-family:monospace;}
.text.source-text .imp {font-weight: bold; color: red;}
.text.source-text li, .text.source-text .li1 {font-weight: normal; vertical-align:top;}
.text.source-text .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}
.text.source-text .li2 {font-weight: bold; vertical-align:top;}
.text.source-text .ln-xtra, .text.source-text li.ln-xtra, .text.source-text div.ln-xtra {background-color: #ffc;}
.text.source-text span.xtra { display:block; }

/*]]>*/
</style>
<!--[if lt IE 7]><style type="text/css">body{behavior:url("/mwiki/skins/cppreference2/csshover.min.htc")}</style><![endif]-->
</head>
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_variadic skin-cppreference2 action-view">
        <!-- header -->
        
        <!-- /header -->
        <!-- content -->
        <div id="cpp-content-base">
            <div id="content">
                <a id="top"></a>
                <div id="mw-js-message" style="display:none;"></div>
                                <!-- firstHeading -->
                <h1 id="firstHeading" class="firstHeading">Variadic functions</h1>
                <!-- /firstHeading -->
                <!-- bodyContent -->
                <div id="bodyContent">
                                        <!-- tagline -->
                    <div id="siteSub">From cppreference.com</div>
                    <!-- /tagline -->
                                        <!-- subtitle -->
                    <div id="contentSub"><span class="subpages">&lt; <a href="../c.html" title="c">c</a></span></div>
                    <!-- /subtitle -->
                                                            <!-- bodycontent -->
                    <div id="mw-content-text" lang="en" dir="ltr" class="mw-content-ltr">
<p><a href="http%3A//en.cppreference.com/mwiki/index.php" class="new" title="Template:c/variadic/navbar (page does not exist)">Template:c/variadic/navbar</a>
</p>
<p>Variadic functions are functions (e.g. <span class="t-lc"><a href="io/fprintf.html" title="c/io/fprintf">printf</a></span>) which take a variable number of arguments.
</p>
<p>The declaration of a variadic function uses an ellipsis as the last parameter, e.g. <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">int</span> <a href="io/fprintf.html"><span class="kw851">printf</span></a><span class="br0">(</span><span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> format, ...<span class="br0">)</span><span class="sy4">;</span></span></span>. See <a href="http%3A//en.cppreference.com/mwiki/index.php" class="new" title="c/language/variadic arguments (page does not exist)">Variadic arguments</a> for additional detail on the syntax and automatic argument conversions.
</p>
<p>Accessing the variadic arguments from the function body uses the following library facilities:
</p>
<table class="t-dsc-begin">

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code>&lt;stdarg.h&gt;</code> </div>
</td>
</tr>

<tr>
<td colspan="2"> <table id="toc" class="toc"><tr><td>
<div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1"><a href="variadic.html%23Macros"><span class="tocnumber">1</span> <span class="toctext">Macros</span></a></li>
<li class="toclevel-1"><a href="variadic.html%23Type"><span class="tocnumber">2</span> <span class="toctext">Type</span></a></li>
<li class="toclevel-1 tocsection-1"><a href="variadic.html%23Example"><span class="tocnumber">3</span> <span class="toctext">Example</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="variadic.html%23See_also"><span class="tocnumber">4</span> <span class="toctext">See also</span></a></li>
</ul>
</td></tr></table>
<h5> <span class="mw-headline" id="Macros">  Macros </span>
</h5>
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="variadic/va_start.html" title="c/variadic/va start"> <span class="t-lines"><span>va_start</span></span></a></div></div>
</td>
<td>   enables access to variadic function arguments <br> <span class="t-mark">(function macro)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="variadic/va_arg.html" title="c/variadic/va arg"> <span class="t-lines"><span>va_arg</span></span></a></div></div>
</td>
<td>   accesses the next variadic function argument <br> <span class="t-mark">(function macro)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div">
<div><a href="variadic/va_copy.html" title="c/variadic/va copy"> <span class="t-lines"><span>va_copy</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
</div>
</td>
<td>   makes a copy of the variadic function arguments  <br> <span class="t-mark">(function macro)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="variadic/va_end.html" title="c/variadic/va end"> <span class="t-lines"><span>va_end</span></span></a></div></div>
</td>
<td>   ends traversal of the variadic function arguments <br> <span class="t-mark">(function macro)</span> 
</td>
</tr>


<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Type">  Type </span>
</h5>
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="variadic/va_list.html" title="c/variadic/va list"> <span class="t-lines"><span>va_list</span></span></a></div></div>
</td>
<td>   holds the information needed by va_start, va_arg, va_end, and va_copy <br> <span class="t-mark">(typedef)</span> 
</td>
</tr>
</table>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Example">edit</a>]</span> <span class="mw-headline" id="Example">Example</span>
</h3>
<div class="t-example">
<p> Print values of different types.
 </p>
<div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">Run this code</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="c source-c"><pre class="de1"><span class="co2">#include &lt;stdio.h&gt;</span>
<span class="co2">#include &lt;stdarg.h&gt;</span>
 
<span class="kw4">void</span> simple_printf<span class="br0">(</span><span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> fmt,...<span class="br0">)</span>
<span class="br0">{</span>
    va_list args<span class="sy4">;</span>
    va_start<span class="br0">(</span>args, fmt<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">while</span> <span class="br0">(</span><span class="sy2">*</span>fmt <span class="sy3">!</span><span class="sy1">=</span> <span class="st0">'<span class="es5">\0</span>'</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">if</span> <span class="br0">(</span><span class="sy2">*</span>fmt <span class="sy1">==</span> <span class="st0">'d'</span><span class="br0">)</span> <span class="br0">{</span>
            <span class="kw4">int</span> i <span class="sy1">=</span> va_arg<span class="br0">(</span>args, <span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
            <a href="io/fprintf.html"><span class="kw851">printf</span></a><span class="br0">(</span><span class="st0">"%d<span class="es1">\n</span>"</span>, i<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span> <span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span><span class="sy2">*</span>fmt <span class="sy1">==</span> <span class="st0">'c'</span><span class="br0">)</span> <span class="br0">{</span>
            <span class="co1">// note automatic conversion to integral type</span>
            <span class="kw4">int</span> c <span class="sy1">=</span> va_arg<span class="br0">(</span>args, <span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
            <a href="io/fprintf.html"><span class="kw851">printf</span></a><span class="br0">(</span><span class="st0">"%c<span class="es1">\n</span>"</span>, c<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span> <span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span><span class="sy2">*</span>fmt <span class="sy1">==</span> <span class="st0">'f'</span><span class="br0">)</span> <span class="br0">{</span>
            <span class="kw4">double</span> d <span class="sy1">=</span> va_arg<span class="br0">(</span>args, <span class="kw4">double</span><span class="br0">)</span><span class="sy4">;</span>
            <a href="io/fprintf.html"><span class="kw851">printf</span></a><span class="br0">(</span><span class="st0">"%f<span class="es1">\n</span>"</span>, d<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span>
        <span class="sy2">++</span>fmt<span class="sy4">;</span>
    <span class="br0">}</span>
 
    va_end<span class="br0">(</span>args<span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
<span class="br0">{</span>
    simple_printf<span class="br0">(</span><span class="st0">"dcff"</span>, <span class="nu0">3</span>, <span class="st0">'a'</span>, <span class="nu16">1.999</span>, <span class="nu16">42.5</span><span class="br0">)</span><span class="sy4">;</span> 
<span class="br0">}</span></pre></div></div>
<p>Output:
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">3
a
1.999000
42.50000</pre></div></div> 
</div>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: See also">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span>
</h3>
<table class="t-dsc-begin">

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td colspan="2"> <div class="t-dsc-see">
<span><a href="../cpp/utility/variadic.html" title="cpp/utility/variadic">C++ documentation</a></span> for <span class="t-dsc-see-tt"><span>Variadic functions</span></span>
</div>
</td>
</tr>

</table>

<!-- 
NewPP limit report
Preprocessor visited node count: 769/1000000
Preprocessor generated node count: 2240/1000000
Post‐expand include size: 23129/2097152 bytes
Template argument size: 5695/2097152 bytes
Highest expansion depth: 20/40
Expensive parser function count: 0/100
-->

<!-- Saved in parser cache with key mwiki1-mwiki_en_:pcache:idhash:13690-0!*!0!!en!*!* and timestamp 20140623202229 -->
</div>                    <!-- /bodycontent -->
                                        <!-- printfooter -->
                    <div class="printfooter">
                    Retrieved from "<a href="http%3A//en.cppreference.com/mwiki/index.php">http://en.cppreference.com/mwiki/index.php?title=c/variadic&amp;oldid=71747</a>"                    </div>
                    <!-- /printfooter -->
                                                            <!-- catlinks -->
                    <div id="catlinks" class="catlinks catlinks-allhidden"></div>                    <!-- /catlinks -->
                                                            <div class="visualClear"></div>
                    <!-- debughtml -->
                                        <!-- /debughtml -->
                </div>
                <!-- /bodyContent -->
            </div>
        </div>
        <!-- /content -->
        <!-- footer -->
        
        <!-- /footer -->
        <script>if(window.mw){
mw.loader.state({"site":"loading","user":"missing","user.groups":"ready"});
}</script>
<script src="../../common/skin_scripts.js"></script>
<script>if(window.mw){
mw.loader.load(["mediawiki.action.view.postEdit","mediawiki.user","mediawiki.page.ready","mediawiki.searchSuggest","mediawiki.hidpi","ext.gadget.ColiruCompiler"], null, true);
}</script>
<script src="../../common/site_scripts.js"></script>

<script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-2828341-1']);
_gaq.push(['_setDomainName', 'cppreference.com']);
_gaq.push(['_trackPageview']);
</script><!-- Served in 0.083 secs. -->
	</body>
<!-- Cached 20140623212803 -->
</html>
